JP2005259073A - Electronic apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To switch connection of a USB without causing any confusion in a user. <P>SOLUTION: An MD player 10 counts a delay time serving as an argument of a switch interface and starts monitoring a signal line when a command instructing switch of USB connection called as the switch interface. When the signal line is suspended, the MD player 10 starts disconnection/connection processing of the USB even if the delay time does not pass. When the signal line is not suspended, the MD player 10 outputs a suspend interruption request after waiting for the delay time and suspends the signal line. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an electronic device that can be connected to an external device via a USB.

  An interface called USB (Universal Serial Bus) exists as a general-purpose interface for connecting a personal computer and an external device. USB is a serial interface for PCs that has emerged to replace medium- and low-speed interfaces such as serial ports and parallel ports. A single PC (host) is the center for connecting various peripheral devices (nodes). Take. USB supports plug-and-play, does not require settings for each connected device, and supports a hot plug / unplug function that allows peripheral devices to be freely attached and detached while the power is on. Furthermore, in recent years, a standard called On-The-Go has appeared as a USB standard, and it has become possible to connect peripheral devices without using a PC.

  The USB system takes a form in which a peripheral device as a client is connected mainly by a host (for example, a PC). An application is stored in the host, and the application requests the OS to control the device. One of the commands output from the application to the OS is a switch interface. The switch interface is a command for switching the USB connection without physically removing the USB. The USB connection switching includes a phase in which the USB signal line is suspended and a phase in which reconnection is performed.

  In different types of OSs, the timing to start suspend may be different even if the same switch interface command is input. Specifically, a command called a switch interface can set a waiting time from when the command is issued until it is suspended. Some OSs start suspending when the waiting time elapses, and others start suspending even if the waiting time is not completed when the preparation on the OS side is completed.

  In the switch interface, the reconnection start time is determined in accordance with the standby time. If the OS starts suspend without waiting for the standby time, the suspended state continues until the reconnection start time. Since the OS does not recognize the suspended device, the suspended device is displayed on the display unit of the host as “unknown device”. The indication “unknown device” may confuse the user.

  An object of the present invention is to provide an electronic device that switches a USB connection without confusing a user.

  In order to solve the above-described problems, an electronic device according to the present invention is an electronic device connected to an external device via a USB, a command input unit that inputs a USB connection switching command from the external device, and a USB A connection switching unit that virtually disconnects and connects the device, a detection unit that detects USB suspend, and when the command input unit inputs a command, causes the detection unit to start detecting suspend, and when the detection unit detects USB suspend. The connection switching means includes start control means for starting disconnection and connection of the USB.

  According to the present invention, when the USB connection is switched, the USB suspend is monitored, and when the suspend is detected, the USB disconnection and connection are started. As a result, the time in the suspended state is shortened and the display of the display unit “unknown device” of a host such as a personal computer is not caused.

  The present invention relates to a USB (Universal Serial Bus) connection switching process in an MD (Mini Disc; registered trademark) player. In the switching process of the USB connection, a state in which the USB is connected / disconnected by electrical control is virtually generated without physically connecting / disconnecting the USB. Since the USB supports plug and play, the USB connection is automatically started by using the USB insertion / extraction as a trigger, and the setting before the USB extraction is updated to the setting after the USB insertion.

  USB virtual insertion / removal is a process executed after the USB signal line is suspended. Suspend of the signal line is started on the host side. Host OS (Operating System) includes a suspend start (first OS) according to a request from a device and an OS (second OS) that spontaneously starts suspend. When the PC is controlled by the first OS, the device recognizes the timing of transition to suspend, and can immediately start disconnection / connection of the USB after transition to suspend.

  On the other hand, when the PC is controlled by the second OS, the device cannot grasp the start of suspend by the OS, and therefore cannot start the next process immediately after being suspended. When the time from the start of the suspend to the start of the next process becomes longer, the PC displays the MD player on the display unit as an “unknown device”. Since the display of “unknown device” may confuse the user, the suspend time should be sufficiently shortened to avoid the display of “unknown device”.

  The MD player according to the present invention monitors the state of the signal line and, when detecting the suspend issued spontaneously by the OS, immediately starts the next process, thereby shortening the suspend period and displaying “unknown device”. It is characterized by avoiding.

  The configuration of the MD player to which the present invention is applied and the specifications of the MD that can be reproduced by the MD player will be described below. The MD player is a device for recording and reproducing data on a disk-like magneto-optical recording medium having a diameter of about 6.4 cm housed in a cartridge as a disk-like magneto-optical recording medium. Furthermore, the MD player according to the present embodiment records and reproduces the disc-shaped magneto-optical recording medium having three different recording formats. One is a magneto-optical disk to which a so-called MD (registered trademark) format is applied. The other is a magneto-optical disk to which a format called “next generation MD1” is applied. The last one is a magneto-optical disk to which a format called “next generation MD2” is applied. The so-called MD is usually used as a format dedicated to audio data, but may be used for data recording (MD-DATA).

  First, specifications of conventional MD, next generation MD1, and next generation MD2 will be described. FIG. 1 shows disk specifications of conventional MD (MD-DATA), next generation MD1, and next generation MD2.

  Conventional MD physical specifications are: track pitch 1.6 μm, pit length 0.59 μm / bit, laser wavelength λ 780 nm, objective lens numerical aperture NA 0.45, disk recording method groove recording, address method A single spiral groove is wobbled on both sides at a predetermined frequency (22.05 kHz), and the absolute address (ADIP) is FM-modulated to that frequency, the modulation method is EFM (8-14 conversion), and the error correction method is ACIRC (Advanced Cross Interleave Reed-Solomon Code), interleaving method is convolution method, redundancy is 46.3%, data detection method is bit-by-bit method, disk drive method is CLV (Constant Linear Velocity) method, linear velocity is 1 .2m / s, data rate is 133KB / s, and recording capacity is 164MB (when used as MD DATA) 140MB), the minimum writing unit is 32 sectors and 36 sectors with 4 link sectors. In this conventional MD, data is recorded from the inner circumference side to the outer circumference side along the track.

  The physical specifications of the next-generation MD1 are: track pitch is 1.3 μm, pit length is 0.44 μm / bit, laser wavelength λ is 780 nm, objective lens numerical aperture NA is 0.45, disk recording method is groove recording, addressing method Is a single spiral groove wobbled at a predetermined frequency (22.05kHz) and FM modulation of absolute address (ADIP) to that frequency, the modulation method is RLL1-7PP (Run Length Limited 1-7 Parity Preserve / Prohibit rmtr) method, error correction method is RS-LDC (Read-Solomon Long Distance Code) with BIS (Burst Indicator Subcode), interleave method is block completion method, redundancy is 20.50%, data detection method is Viterbi decoding method using PR (1, 2, 1) ML, disk drive method is CLV (Constant Linear Velocity) method, linear velocity There 2.4 m / s, the data rate is 4.4MB / s, the recording capacity is 300MB, the minimum write unit is turned 16 sectors, and. In the next generation MD1, data is recorded from the inner circumference side toward the outer circumference side along the track.

  Such a next-generation MD1 has the same physical configuration as a conventional MD. In other words, the next generation MD1 is formed by formatting the conventional MD in the next generation MD format. However, in the next generation MD1, the window margin is changed from 0.5 to 0.666 by changing the modulation method from EFM to RLL (1-7) PP, 1.33 times higher than the current MD. Densification is realized. Also, by changing the recording modulation method from CIRC method to RS-LDC method with BIS and using sector structure difference and Viterbi decoding, the data efficiency is changed from 53.7% to 79.5%, compared with the current MD. As a result, the density is increased by 1.48 times. With the above specifications, even if the disc itself is the same as the current MD, the recording capacity can be made 300 MB, which is about twice that of the current MD.

  The physical specifications of the next-generation MD2 are: track pitch: 1.25 μm, pit length: 0.16 μm / bit, laser wavelength λ: 780 nm, objective lens numerical aperture NA: 0.45, disk recording method: groove recording and domain wall motion Detection (DWDD) system, address system is a single spiral groove, both sides are wobbled at a predetermined frequency (22.05 kHz), and absolute address (ADIP) is FM-modulated to that frequency, modulation system is RLL1-7PP (Run Length Limited 1-7 Parity Preserve / Prohibit rmtr) method, error correction method is RS-LDC (Read-Solomon Long Distance Code) with BIS (Burst Indicator Subcode), interleave method is block completion method, redundancy is 20 50%, Viterbi decoding method with PR (1, -1) ML as data detection method, CL as disk drive method (Constant Linear Velocity) method, the linear velocity is 2.0 m / s, the data rate is 9.8MB / s, the recording capacity is 1GB, the minimum write unit is in the 16 sectors. In the next generation MD2, data is recorded from the inner circumference side toward the outer circumference side along the track.

  The next generation MD2 has the same outer shape as the conventional MD and the next generation MD1. However, the structure of the disk itself is different.

  The next-generation MD2 disk uses a magnetic super-resolution technique to improve the recording capacity in the linear density direction. In the magnetic super-resolution technology, when a predetermined temperature is reached, the cut layer becomes magnetically neutral, and the magnetic wall transferred to the recording layer is transferred, so that a minute mark can be seen in the beam spot. It is a thing using what becomes.

  That is, in the next-generation MD2 disc, at least a magnetic layer serving as a recording layer for recording information, a cutting layer, and a magnetic layer for reproducing information are stacked on a transparent substrate. The cutting layer is an exchange coupling force adjusting layer. When the temperature reaches a predetermined temperature, the cut layer becomes magnetically neutral, and the domain wall transferred to the recording layer is transferred to the reproducing magnetic layer. As a result, minute marks can be seen in the beam spot. At the time of recording, a minute mark can be generated by using a laser pulse magnetic field modulation technique.

  Further, the optical system, the reading method, the servo processing, and the like are the same in order to adopt compatibility with the current MD and the next-generation MD1. However, when reading a narrower track pitch and linear density (bit length) than the conventional one using an optical system equivalent to the current MD and the next generation MD1, the crossing from the detrack margin, land and groove is used. It is necessary to eliminate constraints on talk, wobble crosstalk, focus leakage, CT signals, and the like. Therefore, in the next generation MD2, the groove depth, inclination, width and the like of the groove are changed. Specifically, the groove depth of the groove is determined to be 160 nm to 180 nm, the inclination is 60 ° to 70 °, and the width is 600 nm to 800 nm.

  Next, the configuration of the MD player will be described. As shown in FIG. 2, the MD player 10 includes a media drive unit 11, a memory transfer controller 12, a nonvolatile memory 13, a RAM 14, a USB device controller 15, a system controller 18, and an audio processing unit 19. . The MD player is connected to the PC 20 via the USB cable 111.

  The media drive unit 11 performs recording / reproduction with respect to each MD 90 such as a loaded conventional MD or next generation MD. Conventional MD is MD for the purpose of recording music information, and the modulation method is EFM. The next generation MD includes a recording area as a storage medium of a PC in addition to a recording area for music information. The modulation method of the next generation MD is RLL (1-7) PP, which has a higher density than the conventional MD.

  The USB device controller 15 performs USB transmission control. The RAM 14 buffers data read from the data track of the MD 90 by the media drive unit 11 in units of high-density data clusters based on the control of the system controller 18. The RAM 14 stores various management information and special information such as UTOC data, FAT data, unique ID, and hash value read from the MD 90 by the media drive unit 11 based on the control of the system controller 18.

  The system controller 18 can communicate with the PC 20 connected via the USB, performs communication control with the PC 20, receives commands such as a write request and a read request, status information, etc. The necessary information is transmitted, and the MD player 10 is totally controlled.

  For example, when the MD 90 is inserted in the media drive unit 11, the memory transfer controller 12 instructs the media drive unit 11 to read management information from the MD 90, and stores the read management information such as PTOC and UTOC in the RAM 14. To store.

  The memory transfer controller 12 can grasp the track recording state of the MD 90 by reading the management information. Further, by reading the FAT, the cluster structure in the data track can be grasped, and the access request to the data track from the PC 20 can be handled.

  Also, the disk authentication process and other processes are executed based on the unique ID and the hash value, or these values are transmitted to the PC 20 to execute the disk authentication process and other processes on the PC 20.

  The memory transfer controller 12 transfers the data stored in the RAM 14 to the media drive unit 11 as recording data. At this time, the media drive unit 11 modulates the recording data by the EFM modulation method if the mounted medium is the conventional MD, and by the RLL (1-7) PP modulation method if the medium is the next generation MD1 or the next generation MD2. Write.

  In the MD player 10 shown as this specific example, the recording / reproduction control described above is control when recording / reproducing data tracks, and data transfer when recording / reproducing MD audio data (audio tracks) is performed by audio processing. This is performed via the unit 19.

  The audio processing unit 19 includes, for example, an analog audio signal input unit such as a line input circuit / microphone input circuit, an A / D converter, and a digital audio data input unit as an input system. The audio processing unit 19 includes an ATRAC compression encoder / decoder and a compressed data buffer memory. Further, the audio processing unit 19 includes an analog audio signal output unit such as a digital audio data output unit, a D / A converter, and a line output circuit / headphone output circuit as an output system.

  An audio track is recorded on the MD 90 when digital audio data (or an analog audio signal) is input to the audio processing unit 19. Linear PCM audio data that is input as linear PCM digital audio data or analog audio signals and then converted by an A / D converter is subjected to ATRAC compression encoding and stored in a buffer memory. Thereafter, the data is read from the buffer memory at a predetermined timing (data unit corresponding to the ADIP cluster) and transferred to the media drive unit 11.

  In the media drive unit 11, the transferred compressed data is modulated by the EFM modulation method or the RLL (1-7) PP modulation method, and written in the MD 90 as an audio track. When reproducing the audio track from the MD 90, the media drive unit 11 demodulates the reproduction data into the ATRAC compressed data state and transfers it to the audio processing unit 19. The audio processing unit 19 performs ATRAC compression decoding to obtain linear PCM audio data, which is output from the digital audio data output unit. Alternatively, line output / headphone output is performed as an analog audio signal by a D / A converter.

  Next, the structure of software for controlling the PC 20 and the MD player 10 will be described with reference to FIG. As described above, the MD player 10 to which the present invention is applied is a multi-disc player that reproduces two types of MD 90, a next-generation MD and a conventional MD. The MD player 10 can be connected to the PC 20 via the USB. The PC 10 stores an MD management application 25 that edits and manages data recorded in the MD 90.

  The MD management application 25 operates on the OS 22. The MD management application 25 instructs the OS 22 to control USB. The OS 22 includes a device driver 23 and controls the MD player 10 and the USB host controller 21 in accordance with instructions from the MD management application 25.

  The MD management application 25 issues a system call to the OS 22 to instruct USB control. One of system calls issued from the MD management application 25 to the OS 22 is switching of USB connection. The USB connection switching is processing for changing the USB connection setting from the current setting to the new setting. This system call is issued when the MD 90 attached to the MD player 10 is replaced or when the MD 90 is formatted. This is because when the format of the MD90 changes, it is necessary to load a USB communication protocol, communication command, and driver suitable for the MD90 format.

  When the OS 22 is instructed to switch the USB connection, the OS 22 starts the connection switching process 24. The connection switching process 24 executes a connection / disconnection process on the PC side and outputs a command called a switch interface to the MD player 10. The MD player 10 that has received the switch interface executes USB connection switching processing in cooperation with the PC 20. More specifically, the MD player 10 waits for the signal line to be suspended, and activates the connection switching event 16 when the signal line is suspended. The connection switching event 16 is an event for virtually inserting / removing USB without physically removing / inserting the USB. By processing this event, the USB initialization is automatically started, the USB setting before the USB is pulled out is deleted, and the USB setting after the insertion is updated.

  The above processing is executed after the signal line is suspended. The timing at which the signal line is suspended differs depending on the type of the OS 22. As described above, the OS 22 includes the first OS that suspends the signal line according to the request of the MD player 10 and the second OS that spontaneously starts the suspend. When the first OS controls the PC, the OS continues to output SOF as shown in FIG. The MD player counts the delay time, and outputs a suspend interrupt request to the OS when the delay time elapses. The first OS suspends the signal line in response to the suspend interrupt request from the MD player 10. On the other hand, when the second OS controls the PC, as shown in FIG. 4B, the OS starts suspending without waiting for the delay time when the signal line condition on the PC side is satisfied. To do.

  The delay time is an argument of the switch interface. The delay time is a waiting time from when the MD player inputs the switch interface to when the USB disconnection / connection is started.

  When the signal line is suspended, the PC 20 does not recognize the device, so the MD player 10 is displayed as “unknown device” on the display unit of the PC 20. The indication “unknown device” may confuse the user. Since the MD player 10 to which the present invention is applied does not display “unknown device”, when the signal line enters the suspended state, the connection switching event 16 is activated immediately without waiting for the delay time.

  The MD player 10 monitors the output of a signal called SOF (Start Of Frame) in order to detect suspend. SOF is a USB synchronization signal and is issued every 1 ms. The SOF is a signal that is constantly issued during USB communication. When the SOF is not issued, the signal line can be determined to be in a suspended state.

  When detecting the stop of the SOF, the MD player 10 disconnects the signal line and pulls up the signal line D + even if the delay time has not elapsed. In the USB standard, when the signal line D + is pulled up, the USB is inserted and the USB connection is automatically started. The connection procedure is defined by the USB standard, but in brief, it consists of detecting the bus speed, exchanging attribute information (descriptor), and setting the logical address (endpoint) of the device. .

  The operation of the MD player 10 described above will be described with reference to FIG. When the OS 22 issues a switch interface to the MD player 10 (step S11), the MD player 10 sets a flag indicating that the switch interface has been received. This flag is called an SI flag (step S12).

  Next, the MD player 10 starts two processes of delay time counting and signal line monitoring. The MD player 10 monitors the signal line (step S13), and when the signal line is suspended (step S14; YES), checks the SI flag. When the SI flag is set, the MD player 10 determines that this suspend is a suspend by the switch interface, and generates a connection switching event 16 (step S15).

  On the other hand, the MD player 10 counts the delay time (step S16), and outputs a suspend interrupt request to the PC 20 when the delay time has elapsed. The OS (first OS) generates a suspend interrupt according to this request (step S17). When detecting the suspend, the MD player 10 checks the SI flag, and activates the connection switching event 16 when the SI flag is set (step S15).

  The connection switching event 16 pulls up the signal line D + after setting the signal line to the Detach state. Thus, the signal line is pulled out and inserted, and the USB logical connection is started (step S18).

  Note that when the signal line is inserted, the PC 20 switches the signal line to the bus reset state. When the signal line is reset to the bus, communication is performed between the PC 20 and the MD player 10, and the PC detects the bus speed of the device.

  When the detection of the bus speed is completed, the PC 20 outputs a file called a device request to the MD player 10. In the device request, a list of information necessary for USB logical connection is described. The MD player 10 generates a descriptor describing information necessary for connection based on the contents of the device request. The format of the descriptor is determined by the USB specification. The descriptor must describe a USB specification release number, class code, subclass code, protocol code, vendor ID, product ID, and the like.

  In the descriptor, information for specifying a device is described. Therefore, when the reconnection process is completed, the “device name” described in the descriptor can be displayed on the display unit. Since it takes about several tens of milliseconds to receive the descriptor after resetting the signal line, “unknown device” is not displayed on the display unit of the PC 20. Or even if displayed, it is a very short time, and the user cannot visually recognize it.

  Next, the PC 20 assigns a unique address to the device. This address is called an end point. Then, based on the information in the device descriptor, the related class driver and other client drivers are loaded, and communication between the driver and the device is started. Here, the USB connection switching is completed.

  As described above, in the MD player 10 to which the present invention is applied, when switching the USB connection, the output of the USB SOF is monitored, and when the SOF output stop is detected, the USB reconnection is started. As a result, the time in the suspended state is shortened and the display of “unknown device” is not displayed on the display unit of the PC 20.

  In addition, since reconnection is started immediately after entering suspend, the time required for switching the USB connection can be reduced.

It is the figure which described the attribute of conventional MD and next generation MD. It is a block diagram which shows the internal structure of MD player. It is a schematic diagram which shows the structure of the software of MD player and PC. It is a schematic diagram which shows the timing until it starts a suspend. It is a flowchart which shows operation | movement of MD player to which this invention is applied.

Explanation of symbols

10 MD player, 11 media drive, 12 memory transfer controller, 15 USB device controller, 16 connection switching event, 18 system controller, 20 PC, 21 USB host controller, 22 OS, 23 device driver, 24 connection switching process, 25 MD Management application

Claims (4)

An electronic device connected to an external device via USB (Universal Serial Bus),
Command input means for inputting a USB connection switching command from the external device;
Connection switching means for virtually disconnecting and connecting the USB;
Detecting means for detecting the USB suspend;
When the command input means inputs a command, the detection means starts detection of suspend, and when the detection means detects USB suspend, the connection switching means starts start of USB disconnection and connection. An electronic device characterized by that. A counting means for counting a predetermined delay time;
The start control means causes the connection switching means to start disconnection and connection of the USB when the detection means does not detect suspend and the counting means counts the delay time. The electronic device according to claim 1.   The electronic device according to claim 2, wherein the delay time is described in the command.   2. The electronic apparatus according to claim 1, wherein the detection unit determines whether or not the signal line is suspended depending on whether or not USB SOF (Start Of Frame) is stopped.

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